Mr. Gomi recalled that during one interview at a bar in Beijing in May 2011 the late dictator’s first-born son threw back whiskey so quickly, drinking five times faster than the journalist, that he was concerned for his subject’s health.

But Mr. Gomi said Kim Jong Nam, who gained a certain kind of playful notoriety when in 2001 he was caught sneaking into Japan to visit Tokyo Disneyland, is quite the opposite from what headlines may suggest. Instead, he’s “well-read,” “intelligent,” “sensible” and in some respects “ordinary.” He is someone who is deeply concerned about his home country and someone you’d want to befriend, said Mr. Gomi, speaking at a news conference on Tuesday at the Tokyo Foreign Correspondents’ Club.

Mr. Gomi said during their correspondence he sent Kim Jong Nam, who has been living in Beijing since 1995, books about his reclusive home country that were published in South Korea. But Mr. Kim always said he had naturally already read them.

The 40-something-year-old Beijing transplant was also on top of any news about North Korea. When Mr. Gomi emailed him for comment shortly after Pyongyang’s deadly attack on Yeonpyeong, an island across a disputed maritime border between the two Koreas, in November 2010, the reply came quickly. Mr. Gomi said Mr. Kim surmised the North “had to undertake the action because (the leadership) had to show their people the area was a conflict zone in order to justify the need for increasing military expenditures.”

When he’s not reading up on the news, Mr. Kim told the reporter he “invests money” to earn a living.

Mr. Gomi hypothesizes that the eldest son may be deliberately playing up his role as a carefree hedonist.

“Despite the fact he frequently said he was not interested in North Korean politics, many of his comments had to do with the North Korean economy and political situation, indicating he was concerned and following these issues closely,” said Mr. Gomi. He added that Mr. Kim felt especially apprehensive about returning home after his brother Kim Jong Eun was officially anointed to succeed his father.

Mr. Kim told the Japanese journalist that he felt many more “eyes were watching him” following the announcement because he believed some people suspected he might harbor ambitions to wrest power from his younger brother. “Although he declares that he is not interested in North Korean politics I think he is very concerned and I think he feels it might concern him directly in the future.”

The eldest son, who says he has never met his youngest brother, has not gone back to North Korea for some time. When there are important meetings his wife attends in his place, but it is unclear whether she went to Kim Jong Il’s funeral in his stead.

Associated Press

Japanese journalist Yoji Gomi who published a book titled “My father, Kim Jong Il, and Me.”

Mr. Kim told the journalist that he was constantly being watched in Beijing, but is not sure if it’s to protect him or to monitor his movements. The surveillance is one of the reasons why Mr. Kim says Macau, the Las Vegas of Asia which he often frequents, “suits him better” because “it’s free and he likes to live with great freedom.”

Mr. Gomi also said he gathered the relationship between prodigal son and authoritarian father was a complicated one. Although the prevailing belief was that Kim Jong Il cast his oldest child out after Kim Jong Nam’s failed attempt to visit Tokyo Disneyland, Mr. Kim said that they continued to speak. They occasionally talked on the phone and Mr. Kim expressed his personal views on different topics.

But Mr. Kim, who at the outset said he would not answer Mr. Gomi’s questions about his father’s ailing health, did not speak extensively about the relationship. He simply offered this rule of thumb: “The relationship between a father and son might at times deteriorate, but it always continues and generally improves over time,” said Mr. Kim, as relayed by Mr. Gomi.